In the modern electronics industry integrated circuits and similarly mechanically configured devices frequently are used. Such devices may be, for example, a microprocessor, a read only memory (ROM), a random access memory (RAM), logic arrays, integrated logic circuits, switches, etcetera. These devices usually are mechanically configured to have a three dimensional rectangular or square package body within which the active or passive circuit components, switches, etcetera are contained, and a plurality of electrical leads extending outwardly from the package to provide electrical connections for respective circuits within the package to circuitry externally of the package. More particularly, the package is usually designed for connection to circuitry on a printed circuit board. In many instances, the electrical devices are surface mounted to the circuit board, thereby lowering the profile of the overall structure, and also obviating the requirement for intermediate sockets, such as dual-in-line packages (DIP). In turn, the circuitry on the side of the printed circuit board to which the surface mounted electrical devices connected is, in turn, connected via circuitry included plated through holes to circuitry on the opposite side of the printed circuit board. In many instances, it is desireable to have leads extending from the opposite side of the printed circuit board for connection via a socket to other portions of the electrical system.
Heretofore, in order to connect a plurality of parallel pins to one side of a circuit board opposite to the side on which the chips are surface mounted, the industry has adopted a procedure wherein a plurality of pins are first held within a jig, and a planar plastic carrier is molded about the pins and is disposed orthogonal to the longitudinal axes of the parallel spaced pins. Each pin extends from opposite sides of the planar plastic carrier, and at the corners of the plastic carrier there are provided plastic locator buttons. The printed circuit board similarly includes openings for accommodating the plastic locator buttons. The circuitry on the side of the printed circuit board to which the pins are to be connected have solder pads corresponding to the locations of the pins within the carrier. With the locator buttons being disposed in the corresponding holes in the printed circuit board, one end of each pin engages a solder pad, and the assembly is then placed in an oven where the temperature is brought up very gradually to where the solder melts and thus mechanically and electrically connects the pins to the printed circuit boards. Thereafter, the temperature of the composite structure is brought down very slowly so as to minimize a disconnection of the ends of the pins from the printed circuit board. The problem then faced by the manufacturer is that the printed circuit board would have to again be heated at a later time when the chips are surface mounted to the opposite side of the printed circuit board. In order to minimize the possibility of causing the solder connection of any one pin to the circuit board from being disengaged during reheating, the entire peripheral edge spacing between the printed circuit board and the plastic carrier is encapsulated or sealed with a plastic epoxy. During the subsequent reheating of the assembly in order to form an electrical connection by surface mounting of a chip to the opposite side of the board, if the oven temperature becomes high enough, the heat will melt the solder connection between a pin and the opposite side of the circuit board, thereby rendering the assembly useless. In addition, unless care is taken by the users of the assembly when plugging the pins into a socket or the like, it is possible that one or more leads may be bent or distorted, thereby possibly breaking a solder connection of a pin to the face of the printed circuit board.
Accordingly, it is an object of the subject invention to provide a new and improved printer circuit board electrical adaptor pin which is rigidly connected to a printed circuit board, and which does not require the use of a plastic carrier for holding the adaptor pin prior to connection to a printed circuit board.
It is a further object of the subject invention to provide an improved printed circuit board electrical adaptor pin which forms a rigid and electrically stable connection to a printed circuit board and which does not require encapsulation by a plastic epoxy for shielding the electrical connection from the effects of heat as surface mounted chips are connected to the opposite side of the printed circuit board.